Farewell, Gaia! Spacecraft operations come to an finish

The European Area Company (ESA) has powered down its Gaia spacecraft after greater than a decade spent gathering knowledge that are actually getting used to unravel the secrets and techniques of our residence galaxy.

On 27 March 2025, Gaia’s management staff at ESA’s European Area Operations Heart fastidiously switched off the spacecraft’s subsystems and despatched it right into a “retirement orbit” across the solar.

Although the spacecraft’s operations are actually over, the scientific exploitation of Gaia’s knowledge has simply begun.

Gaia’s stellar contributions

Launched in 2013, Gaia has remodeled our understanding of the cosmos by exactly mapping the positions, distances, motions, and properties of almost 2 billion stars and different celestial objects. It has offered the biggest, most exact multi-dimensional map of our galaxy ever created, revealing its construction and evolution in unprecedented element.

The mission uncovered proof of previous galactic mergers, recognized new star clusters, contributed to the invention of exoplanets and black holes, mapped hundreds of thousands of quasars and galaxies, and tracked a whole lot of hundreds of asteroids and comets. It additionally enabled the creation of the most effective visualization of how our galaxy would possibly look to an outdoor observer.

“Gaia’s in depth knowledge releases are a novel treasure trove for astrophysical analysis, and affect virtually all disciplines in astronomy,” says Gaia Venture Scientist Johannes Sahlmann.

“Knowledge launch 4, deliberate for 2026, and the ultimate Gaia legacy catalogs, deliberate for launch no sooner than the tip of 2030, will proceed shaping our scientific understanding of the cosmos for many years to return.”

Saying goodbye is rarely straightforward

Gaia far exceeded its deliberate lifetime of 5 years, and its gas reserves are dwindling. The Gaia staff fastidiously thought-about how greatest to eliminate the spacecraft in keeping with ESA’s efforts to responsibly eliminate its missions.

They needed to discover a technique to stop Gaia from drifting again towards its former residence close to the scientifically beneficial second Lagrange level (L2) of the sun-Earth system and reduce any potential interference with different missions within the area.

“Switching off a spacecraft on the finish of its mission appears like a easy sufficient job,” says Gaia Spacecraft Operator Tiago Nogueira. “However spacecraft actually do not wish to be switched off.”

“Gaia was designed to resist failures equivalent to radiation storms, micrometeorite impacts or a lack of communication with Earth. It has a number of redundant programs that guarantee it may at all times reboot and resume operations within the occasion of disruption.”

“We needed to design a decommissioning technique that concerned systematically choosing aside and disabling the layers of redundancy which have safeguarded Gaia for thus lengthy, as a result of we do not need it to reactivate sooner or later and start transmitting once more if its photo voltaic panels discover daylight.”

On 27 March 2025, the Gaia management staff ran by means of this collection of passivation actions. One ultimate use of Gaia’s thrusters moved the spacecraft away from L2 and right into a steady retirement orbit across the solar that may reduce the prospect that it comes inside 10 million km of Earth for a minimum of the subsequent century.

The staff then safely deactivated and switched off the spacecraft’s devices and subsystems one after the other, earlier than intentionally corrupting its onboard software program. The communication subsystem and the central laptop had been the final to be deactivated.

“At the moment, I used to be in command of corrupting Gaia’s processor modules to make it possible for the onboard software program won’t ever restart once more as soon as we’ve switched off the spacecraft,” says Spacecraft Operations Engineer, Julia Fortuno.

“I’ve blended emotions between the thrill for these vital end-of-life operations and the unhappiness of claiming goodbye to a spacecraft I’ve labored on for greater than 5 years. I’m very blissful to have been a part of this unimaginable mission.”

Gaia’s ultimate transmission to ESOC mission management marked the conclusion of an intentional and punctiliously orchestrated farewell to a spacecraft that has tirelessly mapped the sky for over a decade.

A long-lasting legacy

Although Gaia itself has now gone silent, its contributions to astronomy will proceed to form analysis for many years. Its huge and increasing knowledge archive stays a treasure trove for scientists, refining data of galactic archaeology, stellar evolution, exoplanets and rather more.

A workhorse of galactic exploration, Gaia has charted the maps that future explorers will depend on to make new discoveries. The star trackers on ESA’s Euclid spacecraft makes use of Gaia knowledge to exactly orient the spacecraft. ESA’s upcoming Plato mission will discover exoplanets round stars characterised by Gaia and should comply with up on new exoplanetary programs found by Gaia.

The Gaia management staff additionally used the spacecraft’s ultimate weeks to run by means of a collection of know-how assessments. The staff examined Gaia’s micro-propulsion system below completely different difficult situations to look at the way it had aged over greater than ten years within the harsh setting of house. The outcomes could profit the event of future ESA missions counting on related propulsion programs, such because the LISA mission.

Perpetually in Gaia’s reminiscence

The Gaia spacecraft holds a deep emotional significance for many who labored on it. As a part of its decommissioning, the names of about 1,500 staff members who contributed to its mission had been used to overwrite a few of the back-up software program saved in Gaia’s onboard reminiscence.

Private farewell messages had been additionally written into the spacecraft’s reminiscence, making certain that Gaia will without end carry a chunk of its staff with it because it drifts by means of house.

As Gaia Mission Supervisor Uwe Lammers put it: “We’ll always remember Gaia, and Gaia will always remember us.”